Method of making mixed diglyceride



United States Patent-* r 2,764,605 METHODOF MAKING MIXED DIGLYCERIDE- Norris D. Embree andiGe orge': Y. Brokaw, Rochester,

N. Y., assignors to Eastman Kodak Company, Roche'stery N; Y., a corporation ofNe'w' Jersey NoDrawing, sp iicafimtmi asta, 1952'," SerialNo; 303;!)06

13 Claims; (Cl."260':. 410.'8):

This inventionrelates to methodsof processing fatty triglycerides and to fatty triglyceridederivatives obtained thereby.

Animal and vegetable "fats'a'nd fatty oils consist in large :part: of 'fatty--triglycerides, --i. e. .glyce ry;l fatty; acid tr-iestersz. Forfmany'uses, it"is desirableto--modify;-the ch'emic'al'or physical properties or'bot'hrof; such-fatty trie glyeerides by fo'rmingder-ivatives or mixtures. oft deriva: tives offsuch fatty triglycerides'to obtainproducts suit able for plasticizers, film-forming --fats;easily' digestible fatsor 'the-like. I I r Most, of the naturally occur-ring r-fats; and fatty oils are relatively complex mixtures and similarly the derivatives of such fats and fatty oils arernixtures of materials not readily separable by usual methods and not amenable to'convntiorial'identifiea on techni ues; Thu in-der ivatives er such fats andta v I products' are'apparently dependent upon the-in-t'e'rr ships between many diverse factof's such as te-lat-iv portionsb'f closely 'related mm'poaems, is'emei i state 'ofcrysta-llization "of components and 0th not readily identifiable. As a consequence; =f te'ch nology n large measure "empirieal and the comp 'tion of faftymixtures is a fun'ction of' the inetho'd of processing employed to a 'significant' extent; 9

It is accordingly an object of this invesfieaae' -prwiae new meth ods' -'of processingfatty triglycerides 'toobtain new a'nd'useful compositions of fatty triglyceride 'de rivafives.-

It-is'al'sb 'an obj'ec't of this invention to provide highl-y effective methods ofprep'aring. improved-compositions contain g a'substantialproportion of acyl'at'ed 'glycer'yl fatty acidpartial esters.

Another object" of the invention is to provide mew ine'thods 'ofconverting-fatty triglycerides' in high 'yield to 'pr od ucts having qui't'e"different properties than the fatty tri glyceride's from whichdh'e'y we're prepared.

Another objector the invention is to providemethods for making fatty triglyceride derivatives by". concomitant alcoholysis and ester-interchange.

7 Ahother' obj'ect of the invention is'-toprsvide'eear' c'si ti'ons' ofimproved chemical and physical charaeteilstitis and having an average" composition corresponding to monoa'c'yl inono'glyceride'sl Another object of the invention is--to provide an prov-ed -methddof'making derivatives of triglycerides of higher fatty acids:

Anotherobjet crane-invention is-to 'pfojvide a 1e and efieetivemethodcf converting naturauy occurring fatty-triglyceridesrocompositions containin a substantial proportion-bfinonoaceto monogwcerides and for obt: 1ririg' inate'rialhavingani-average composition corresponding to men'eaceto monoglyeerides" but differing in roperties fl b conventional" menoacetbm'ono'glyferide compostfib'l'lsf' Afro'ther 'objecto'f t-heir'ivention-is-to provide 1 "proved compositions "havingan average'compositi'on 'cor'res'pnu ing to monoacetoglyceryl monostearate.

Other objects will be apparent from the description and claims which follow.

These 'andother' objects are attained by means of this inventionas described more fully hereinafter With parsca a reference to certain preferred embodiments thereof.

Thefatty triglycerides which are processed in accordance with this invention to give products having greatly modified physical and chemical properties include both solid fats andfatty oils, whether obtained from natural sources or -syntheticaly prepared. The invention 'is of particular utilityjin processing the triglycerides of the fatforming higher fatty acids having at least eight carbon atoms in the fatty acid radical. Of greatest practical importance is the processing ofthe naturally occurring fatty triglycerides as found in'animal fats-such'as. lard, or vegetable oils "such as cottonseed oil, soybean oil; peanut oil, cocionuto and the like. I

'rnacedr a ce with this invention, the fatty triglycerides, either'inpurified'form or as mixtures of triglycerides'toget her with other constituents 'of fats and fatty oils, are siibje'cted-toconcomitant alcoholysis and'e ster-interchange b'y co react'ing such fatty triglycerides, glycerine and'an ac'ylated. glycerine in a reaction mixture containing a basic transe'sterification catalyst whereby a reaction product containing a substantial-proporfion'of aylated 'glyceryl fatty acid partial ester is obtained. 'ljhe'deg'ree ofacylation of the a ty tri'gly endsis dpendentu n theniolai' ratio of acylat'e "glycerine to aim well "a's'tlje extent of"acylationfof:fthe acylatedglyc ine, andthe degreeof conversiorr'ofthe fatty triglyceride is a function of the ratio of fatty triglyceride to the combined amount of glycerine and acylated glycerine.

The reaction is promoted-by the presence ofasrhall amount of a basic transesterification catalyst in the reaction mixture. Any of the well-known basic transe'steri'fication-catalysts can be used including'thealkali metals, alkali metal hydrides, alkali metal 'glyceroxides and the like, withthe basic metal hydroxides such as the alkali metal hydroxides and particularly'the bivaleht'met'al hydroxides being desirably employed. Thus, suitable basic transester-ification catalysts includesodium metalgsodiu'm hydride, sodium and potassium glyceroxides, sodium hydroxide; potassium hydroxide, calcium hydroxide, strontiumhydroxide and similar well-known basic transesterificationcatalysts. The amount of' catalystcan be varied inaccordance with usual transesterification-practice-, with amounts of from about 0.001% to about 1;% and particularly from about 0.005% to about 0.1% by Weight based on the total weight of the reaction mixture being preferably employed.

The reaction is effected at elevated temperatures for optimum results with temperatures of at least C. and particularly from about 200 C. to about 280 C. being e'minently suitable. The maxir num'teniperature suitablefor-operations at ordinary pressures is the reflux temperature of the reactants. The reaction time is usually rereaeangthe acylated glycerine and the excess glycerine under the'reaction conditions, especiallyv in the 'caseof an acyltries'tfer of glycerine, to give a premixt ure of glycerine with acylated inorio-, di; and triesters of glycerine. 'The acylatedglycerine canbe monoacyl glycerine, diacyl glyceifiite 'or triacylglycerine or mixtures offtwo or more of such materials in which the acyl radicals contain from 2 to-6 and desirablyil to.4 carbon atoms' Thus suitable ted glycerinesinclude monoacetin, diaeet'in, triacetin iiitures tliereo'f; tributyrin, dibutyrin, monobut'yrin or mixtures thereof; tricaproin, dicaproin, monocaproin or mixtures thereof, or mixtures of any of these or similar acylated glycerines having from 2 to 6 carbon atoms in the acyl radicals with each other.

The reaction mixture obtained usually consists of unreacted glycerine, higher fatty acid triglyceride and acylated glycerine in admixture with substantial amounts of monoacyl monoglycerides, diacyl monoglycerides and monoacyl diglycerides. The resulting reaction product can be used directly if desired, but preferably the unreacted glycerine, fatty triglyceride and acylated glycerine are stripped out and desirably the stripped product is distilled or otherwise separated to give a material having an average composition corresponding to monoacyl monoglyceride. The unreacted glycerine, acylated glycerine and triglycerides can be separated out by solvent extraction, fractional crystallization of the monoacyl monoglycerides from solvent such as petroleum ether at lowered temperatures such as 4 C. or lower, or similar well-known separation procedure, with vacuum distillation and particularly thin film high vacuum distillation at pressures below 300 microns Hg. and temperatures of 160-185 C. or higher being particularly effective to give a product having an average composition corresponding to monoacyl monoglyceride. If desired, however, the product mixture stripped of unreacted glycerine, fat and acylated glycerine can be used without further separation, or varying fractions thereof can be used depending upon the product characteristics desired.

The invention is illustrated by the following examples of preferred embodiments thereof, it being understood'that the examples are not intended to limit the scope of the invention unless otherwise specifically indicated.

Example 1 A mixture of 90 parts by Weight of glycerine, 682 parts by weight of hydrogenated lard and 428 parts by weight of triacetin was charged into a pot reactor equipped with a stirrer. To the mixture was added strontium hydroxide catalyst amounting to 0.12% by weight based on the weight of lard. The mixture was heated at 250 C. and stirred for 5 hours. The resulting reaction mixture was then subjected to distillation on a high vacuum centrifugal still with the unreacted glycerine and glyceryl acetates being stripped out as a strip cut at 135 C. and a pressure below 300 microns Hg. and product recovered as the fraction distilling between 165 and 185 C. The product was obtained in a yield of 46.8% based on the lard weight and was a film forming, plastic material softening at 35 C. and melting at 36 C. Similar results are obtained with other triglyceride fats such as other animal fats and vegetable oils and with triacetin or other acylated glycerines as described hereinabove. I

Example 2 A mixture of monoacetin, diacetin, triacetin and glycerine was prepared by heating a mixture of 244 g. of glycerine, 576 g. of triacetin and 0.065 g. of calcium hydroxide for 90 minutes at 255260 C. To the resulting mixture was added 680 g. of hydrogenated lard and 0.05 g. of calcium hydroxide. This reaction mixture was then heated for 90 minutes at 265 C. after which one-third of the charge was drawn oif and vacuum distilled. The distillate fraction obtained at 185 C. amounted to a yield of 63.3% based on the lard. This product had a softening point of 41 C., a melting point of 4245 C., a hydroxyl value of 118.7 and formed a film which could be bent 180 for 24 times at 27 C. before cracking.

The remaining two-thirds of the charge was heated for an additional 90 minutes, after which half of the product was removed from the reactor and vacuum distilled. The product fraction obtained at 185 C. amounted to a yield of 64.7% based on the lard weight and had a softening v scribed hereinabove.

point of 38 C., a melting point of 41-43.5 C., a saponi- 4 fication number of 291 and withstood twenty bends in film form at 27 C. before cracking.

The remainder of the charge was heated for an additional 3 hours at 265 C. and the product fraction obtained by vacuum distillation at C. represented a yield of 61.2% based on the weight of lard. This product had a softening point of 42 C., a melting point of 4356 C., a hydroxyl value of 119 and a film bend number of 24.

Example 3 A reaction product was prepared by co-reacting glycerine, triacetin and lard in the ratio of 1 mole of glycerine to 1 mole of triacetin, and 6 moles of glycerine plus triacetin to one mole of lard, using 0.008% by weight of calcium hydroxide based on the total charge as catalyst. The distilled product obtained from a 6 hour reaction at 265 C. amounted to a yield of 71.2% based on the lard and had a softening point of 40 C. and a H melting point of 4242.5 C.

Example4 Hydrogenated lard, triacetin and glycerine were reacted in the same molar proportions as in the preceding example using 0.02% by Weight of sodium hydroxide, based on the total charge, as catalyst and a reaction tem-. perature of 220 C. for 3 hrs. The distilled product obtained had a melting point of 36-39 C. and a hydroxyl value of 127.

Similar results are obtained with other fatty triglycerides, acylated glycerines and basic transesterification catalysts employing concentrations and reaction conditions as de-.

The compositions preferably obtained have an average composition corresponding to monoacyl monoglyce'rides. The products can be varied from plastic solids at room temperature in the case of the materials having an average composition corresponding to monoacyl glyceryl monostearates, such as the monoaceto glyceryl monostearates obtained by the co-reaction of lard with acetylated glycerine and glycerine, to liquids which remain fluid at temperatures below 0 C. in the case of the materials having an average composition corresponding to monoacyl glyceryl monooleates, such as the monoaceto glyceryl monooleates obtained by the co-reaction of peanut oil with acetylated glycerine and glycerine. Furthermore the properties of the product can be varied greatly by controlling the degree of acetylation, since, for example, products containing a large amount of monostearin in admixture with a smaller amount of monoaceto and diaceto monostearins have a melting point considerably above room temperature whereas products having an average composition corresponding to diacetomonostearin have a melting point of about 25 to 30 C. The plastic solids formedible coherent films useful as food coatings, and the liquids are useful as food oils, plasticizers and the like. Materials having modified properties can be obtained by blending various monoacyl monoglycerides with each other or with other compatible fatty materials.

Althoughthe invention has been described in considerable detail with reference to certain preferred embodiments thereof, it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim: I

1. The method of processing a fatty triglyceride which comprises effecting concomitant alcoholysis and esterinterchange between a fatty triglyceride wherein the fatty acid radicals each contain at least eight carbon atoms, glycerine and an acylated glycerine wherein the acyl radicals each contain from two to six carbon atoms by co-reacting said fatty triglyceride, glycerine and acylated glycerine in a reaction mixture containing a basic transesterification catalyst to produce a reaction product containing a substantial amount of glyceryl partial ester containing a free hydroxyl group, one of said acyl radicals and one of said fatty acid radicals.

2. The method of processing a fatty triglyceride which comprises co-reacting, in a reaction mixture containing a basic transesterification catalyst, a mixture of fatty triglyceride wherein the fatty acid radicals each contain at least eight carbon atoms, glycerin and an acyl triester of glycerine wherein each acyl group contains from two to six carbon atoms, the combined molar proportions of said acyl triester and said glycerine being greater than the molar proportion of said fatty triglyceride, and thereby eifecting concomitant alcoholysis and ester-interchange to produce a reaction product comprising an admixture of mono-fatty acid monoacyl diesters of glycerine, monofatty acid diacyl triesters of glycerine, di-fatty acid monoacyl triesters of glycerine, glyceryl fatty acid monoesters, and glyceryl fatty acid diesters wherein the acyl groups are said acyl groups from said acyl triester and the fatty acid groups are said fatty acid radicals from said fatty triglyceride, the composition of said reaction product being correlated to the ratio of the reactants in said reaction mixture.

3. The method of processing fatty triglyceride which comprises co-reacting, in a reaction mixture containing a basic transesterification catalyst, a mixture of fatty triglyceride wherein each fatty acid radical contains at least eight carbon atoms, glycerine and an acyl triester of glycerine wherein the acyl groups contain 2 to 6 carbon atoms, said acyl triester and said glycerine being present in substantially equimolar proportions, said co-reacting causing concomitant alcoholysis and ester-interchange and thereby producing a reaction product containing a substantial proportion of monoacyl mono-fatty acid esters of glycerine wherein the acyl groups are from said acyl triester and the fatty acid groups are from said fatty triglyceride.

4. The method of processing fatty triglyceride which comprises co-reacting a fatty triglyceride wherein each fatty acid radical contains at least eight carbon atoms, glycerine and triacetin in the presence of a basic transesterification catalyst and thereby effecting concomitant alcoholysis and ester-interchange effective to produce a reaction product comprising a predominant amount of monoaceto mono-fatty acid diesters of glycerin and a minor amount of diaceto mono-fatty acid triesters of glycerine in admixture with di-fatty acid monoaceto triesters of glycerine, glyceryl fatty acid monoesters and glyceryl fatty acid diesters wherein the fatty acid radicals are from said fatty triglyceride.

5. The method of processing fatty triglycerides which comprises co-reacting a fatty triglyceride selected from the class consisting of animal triglycerides and vegetable triglycerides with glycerine and an acyl triester of glycerine wherein the acyl groups contain from 2 to 6 carbon atoms, in the presence of a basic transesterification catalyst, said fatty triglyceride, glycerine and acyl triester of glycerine being present in correlated amounts with said acyl triester and said glycerine having a predetermined molar ratio and a combined molar amount greater than the molar amount of said triglyceride, said co-reacting effecting concomitant alcoholysis and ester-interchange whereby a reaction product is obtained comprising monoacyl mono-fatty acid diesters of glycerine, diacyl monofatty acid triesters of glycerine and monoacyl di-fatty acid 6 triesters of glycerine in a predetermined ratio correlated to said molar ratio of glycerine and acyl triester.

6. The method of processing triglyceride which comprises co-reacting a fatty triglyceride wherein each fatty acid radical contains at least eight carbon atoms, glycerine and triacetin in the presence of a basic transesterification catalyst, said glycerine and said triacetin being present in substantially equimolar amounts in excess of the molar proportion of fatty triglyceride, said co-reacting causing concomitant alcoholysis and esterinterchange effective to produce a reaction product comprising a mixture of glyceryl esters including a substantial proportion of product having an average composition corresponding to monoaceto mono-fatty acid diester of glycerine.

7. The method of processing triglyceride which comprises co-reacting a fatty triglyceride wherein each fatty acid radical contains at least eight carbon atoms, glycerine and acylated glycerine wherein each acyl group contains from two to six carbon atoms in a reaction mixture containing a basic transesterification catalyst and thereby forming a reaction product including a substantial proportion of monoacyl mono-fatty acid diester of glycerine, and separating by thin film high vacuum distillation said diester from said reaction product.

8. The method of processing fatty triglyceride which comprises co-reacting a fatty triglyceride wherein each fatty acid radical contains at least eight carbon atoms, glycerine and an acyl triester of glycerine wherein each acyl group contains from two to six carbon atoms in a reaction mixture containing a basic transesterification catalyst to effect concomitant alcoholysis and ester-interchange and thereby producing a reaction product comprising a substantial proportion of monoacyl mono-fatty acid diester of glycerine, and separating said diester from said reaction product.

9. The method of processing fatty triglyceride which comprises co-reacting substantially equimolar proportions of glycerine and an acyl triester of glycerine, wherein the acyl groups contain from 2 to 6 carbon atoms, with a leser amount of fatty triglyceride wherein each fatty acid radical contains at least eight carbon atoms in a reaction mixture containing a basic transesterification catalyst, said co-reacting being effective by concomitant alcoholysis and ester-interchange to produce a reaction product comprising a substantial proportion of monoacyl mono-fatty acid diester of glycerine, and separating from said reaction product a material having an average composition corresponding to said diester.

10. The method of processing a triglyceride of higher fatty acids which comprises co-reacting a triglyceride of higher fatty acids having an average composition corresponding to glyceryl tristearate, glycerine, and an acyl triester of glycerine, wherein the acyl groups contain from 2 to 6 carbon atoms, in a reaction mixture containing a basic transesterification catalyst, and separating from the resulting reaction product a material having an average composition corresponding to monoacyl glyceryl monostearate.

11. The method of processing triglycerides which comprises co-reacting a fatty triglyceride containing fat-forming fatty acid radicals having more than 8 carbon atoms, glycerine and an acetylated glycerine mixture comprised of monoacetin, diacetin and triacetin, in the presence of a basic transesterification catalyst, and thereafter separating from the resulting reaction mixture by thin film high vacuum distillation a composition containing a substantial amount of glyceryl partial ester containing a free hydroxyl group, an acetyl radical and one of said fatforming fatty acid radicals.

12. The method of producing acetylated fatty compositions which comprises co-reacting a fatty triglyceride wherein the fatty acid radicals each contain at least 8 carbon atoms, glycerine and an acetylated glyceride selected from the group consisting of (A) triacetin and 7) (=3 anmixtu're 'of monoaeetin; the presence: of abasic, transesterification ca talystg; the molar proportionsv of thwreactants being; correlated to pmdi'lce -'-a reaction 'mixturecomprised 1 predominantly of-t glycerylt pa-rt-ial esters containing; at: leastone free hydnoxyl'zgr'oup including a substantiall-amount-iof glycer'yl; partial -estercontaining afree hydroxyl; group, an acetyl radical I and-one,- of said fattyacid radicals.

13. Theamethod ofproducing-z acetylated: fatty compositions whichJcmprises co-reaetingv a fatty triglyceride wherein'the fatty acid radicals;each-contain at least 8 carbon atoms; g'lyc'erine and an acetylated glyceride selected from the: group; consisting of. (A) triacetin and GBy a mixtil re ofz'monoacetin, diacetin and-triacetin, in the presence of a basic tranesterification catalyst, the molar proportions-of- --the reactants being' correlated to produce=a= reactionmixture; comprised predominantly of glyceryl-partialestersi'containing--at leastone -free hydiacetins andl' triacetini-v-in droxyl group, and thereafter separating frormsaid reactibm mixturesbyw thin film; highvacuum ,1 distillation, 2: composition; 7 containing; a substantial amount of glyceryl partial-ester containing a :free thydroxyl" group,- an: acetyl radical and; :one@ of? said fatty acid. radicals.

-References Cited in the file of thispatent UNITED; STATES PATENTS Schwartz Oct. 20,1 1925 Filachione et al Feb. 12,v 1-952 

1. THE METHOD OF PROCESSING A FATTY TRIGLYCERIDE WHICH COMPRISES EFFECTING CONCOMITANT ALCOHOLYSIS AND ESTERINTERCHANGE BETWEEN A FATTY TRIGLYCERIDE WHEREIN THE FATTY ACID RADICALS EACH CONTAIN AT LEAST EIGHT CARBON ATOMS, GLYCERINE AND AN ACYLATED GLYCERINE WHEREIN THE ACYL RADICALS EACH CONTAIN FROM TWO TO SIX CARBON ATOMS BY CO-REACTING SAID FATTY TRIGLYCERIDE, GLYCERINE AND ACYLATED GLYCERINE IN A REACTION MIXTURE CONTAINING A BASIC TRANSESTERIFICATION CATAYST TO PRODUCE A REACTION PRODUCT CONTAINING A SUBSTANTIAL AMOUNT OF GLYCERYL PARTIAL ESTER CONTAINING A FREE HYDROXYL GROUP, ONE OF SAID ACYL RADICALS AND ONE OF SAID FATTY ACID RADICALS. 